A perennial native, thickstem aster (Eurybia integrifolia) can be found in the Northern Rocky Mountains, Great Basin and Sierra Nevada. It grows in drier meadows, open mountain slopes and disturbed areas from mid to high elevations.
Arising from short, densely fibrous rhizomes, thickstem aster is an erect plant that branches sparingly. Near the base of the plant the leaves are ovate and on short stalks. Higher up the stem the leaves are more lanceolate and become sessile (no stalks). All the leaves have entire margins.
A member of the Sunflower Family (Asteraceae), the flower heads are composed of both ray and disc flowers. The ray flowers are lavender purple. The yellow disc flowers become reddish or brown as they mature and elongate. The bell-shaped involucre is composed of small, pointed, green bracts with purplish tips.
The stems and involucres are hairy and glandular while the leaves are more white-pilose (white, soft hairs).
The fruits are achenes.
Bumblebees and butterflies feed on thickstem asters and serve as pollinators.
Another common name for E integrifolia is entire leaf aster. A synonym is Aster integrifolius. The genus comes from the Greek “eurybies” and means “wide spreading”. In Latin the species designation indicates that the leaf margins are entire.
These thickstem asters were photographed in August along the Pacific Crest Trail in the Warner Valley near Drakesbad (Lassen Volcanic National Park CA).